Valve operating mechanism



Dec. 24, 1963 R." P. LOFINK VALVE OPERATING MECHANISM F iled Sept. 11., 1962- k s M H m N R V m m r m A r S a l R H MMWQ A 8 A I Patented Dec. 24, 1963 3,115,068 VALVE @PERATHNG MECHANISM Raymond P. Lofinlr, Neville island, Pa, assignor, by

rnesne assignments, to Rockwell Manufacturing Cornpany, Pittsburgh, Pa, a corporation of Pennsylvania Filed Sept. 11, 1962., Ser. No. 222,810 4 Claims. C1. 91-414} This application relates to valve operating mechanism, and more particularly to mechanism which is actuated by fluid pressure.

In United States Patent No. 2,95 0,739, there is described and claimed a valve operating mechanism actuated by fluid pressure in which there is a flexible diaphragm, which, when subjected to fluid pressure, actuates a valve to move the valve in one direction, this action of the diaphragm being opposed by a spring. The diaphragm has a deep fold which rolls out to increase the elfective area of the diaphragm as the spring is compressed and increases its resistance to movement of the diaphragm. Such a valve operating mechanism is particularly useful in regulating valves because it provides very close control of the pressure on the outlet or downstream side of the valve without the use of complicated pilot controls which are otherwise required to provide the desired regulation.

Valve operating mechanisms of the type shown in said Lofink Patent No. 2,950,739, have, however, been used only when the outlet or downstream gas pressure was relatively low (i.e., in the order of to 75 pounds) because of the possibility that the diaphragm would rupture under higher outlet pressures whereupon the valve would go to full open position, and the downstream pressure might become dangerously high.

The valve actuating mechanism which I have invented makes it possible to employ the principle of the mechanism described and claimed in the Lofink Patent No. 2,95 0,739 in valves which are operating in lines at relatively high outlet pressures (i.e., in the order of 75 to 250 pounds per square inch), and therefore it will be described with reference to such mechanism. However, my invention can also be used in other types of valve actuating mechanisms employing diaphragms which are subjected to relatively high pressures.

In the accompanying drawings, I have illustrated a presently preferred embodiment of my invention in which:

FIGURE 1 is a vertical section through a regulating valve embodying my invention, and

FIGURE 2 is a section on an enlarged scale of a portion of the section shown in FIGURE 1.

Referring to the drawings, the regulating valve there shown comprises a conventional valve body 3 having an inlet 4 and an outlet 5, a valve seat '6 and a valve disc 7, which cooperates with the seat 6- to regulate the flow of gas through the valve and therefore the pressure of the gas on the downstream or outlet side of the valve. This disc is secured to the end of a valve stem 8 by a crown nut 8a.

The valve stem 8 passes upwardly through a bushing 9 carried in the body 3 and up through a second bushing 10 to a point where it is connected to valve operating mechanism which is actuated by fluid pressure.

A cylinder 11 is held by bolts 12 to the top of the body 3 and is closed at one end by a wall 13 integral with the sides of the cylinder and through which the bushing 10 is threaded. The other end of the cylinder 11 is open. A diaphragm 14 extends across the open end and is secured at its periphery to the cylinder 11 by clamping it between the end of the cylinder and a hollow spring housing 15 which is bolted to the open end of the cylinder 11 by means of bolts 16 which pass through flanges 17 on the housing and flanges 18 on the cylinder adjacent the open end of the cylinder.

The central portion of the diaphragm is clamped between a circular plate 19 and a truncated cone 20, which are held together by connecting rod 21 and which has a portion of enlarged diameter 22 to engage the bottom surface of the plate 19 and which is threaded at its upper end 23 beyond the cone 241. A nut 24 is threaded on the rod 21 to bring the plate 19 and the cone Ztl towards each other and clamp the diaphragm between them.

The lower portion of the plate 19' has a diameter such that it will support an O-ring 25 against the inner walls of the cylinder 11 and act as a piston in the cylinder. The upper portion of the plate 19 has a diameter less than the internal diameter of the cylinder so as to provide a space between the periphery of the upper portion of the plate and the cylinder beneath the diaphragm 14.

The lower end of the connecting rod 21 beneath the enlarged portion 22 has a threaded stud 26 to which the valve stem 8 is secured. The connecting rod 21 has a central bore 2111 into which a stem 27a of a spring button support 27 extends. The spring button 27b carries the lower end of a spring 28- and a spring guide 29 which is secured to the center of the spring button by a pin 30'.

A second spring button 31 engages the top of the spring 28 and is pressed against the spring by an adjusting screw 32 threaded in a top plate 33 which closes the upper end of the housing 15. The stem 26 of the spring button support 27 rests on a ball 34 in the bottom of the bore 21a of the connecting rod 21 so that misalignment of the spring will not affect the position of the plate 19 or cone 2% with respect to the diaphragm and cylinder.

As is apparent from FIGURE 1, the etfect of the spring is to move the valve disc 7 away from the seat 6 and open the valve. This spring force is opposed by fluid under pressure which is supplied to the interior of the cylinder 11 through an inlet 35 in which the case of the pressure regulator here described is connected to a line connected to the downstream side of the valve. Pressure in this line is regulated by the valve to hold it at a predetermined value, as will be explained.

The plate 19 has a passageway 36 which has a vertically extending portion 36a leading from the side of the plate 19 which faces the interior of the cylinder 11. A portion 36b of the passageway 36 has a diameter less than the diameter of the portion 36a, connects to the portion 36:; and leads to the space between the plate 19, and the cylinder 11 beneath the diaphragm 14-. A washer 38 bolted to the plate 19 by a bolt 39 has sufficient diameter to extend part way across the open end of the portion 36a and thereby hold a ball 37 in that portion. The ball coop crates with shoulders 45 formed at the point where the portions 36a and 36b join to act as a ball check valve, as will be subsequently described.

In the regulator shown in the drawings, the housing 15 has an integral bottom 41 in which there is a central opening having a peripheral edge 42 which slopes outwardly and cooperates with the inwardly sloping surface 43 of the cone 2t). Portions of the diaphragm 14 are looped between the surfaces 42 and 43, as shown in the drawings, and these looped portions roll inwardly and outwardly on the edge 42. and surface 4 to increase and decrease the effective area of the diaphragm as resistance of the spring increases and decreases upon compression and extension of the spring. This action of the diaphragm is fully described in Lofink Patent No. 2,950,739.

To operate the valve, pressure exerted by the spring 28 against the diaphragm is adjusted by turning the adjusting screw 32, so that the valve will stay open until pressure on the downstream side of the valve which is communicated to the interior of the cylinder 11 through the inlet 35 reaches a predetermined value. This pressure is also applied to the diaphragm 14 communicated through the passageway 35 in the plate 19. When pressure on the downstream side exceeds this value, it will move the diaphragm to raise the valve stem 9 and close the valve against the pressure of the spring.

In normal operation, fluid under pressure will flow through the passageway 36 into the space between the plate 19 and the cylinder 11 beneath the diaphragm without disturbing the ball 37 since it has a diameter less than the diameter of the passageway portion 36a. If, for any reason, the diaphragm should rupture there will be a sudden surge in the flow of the gas or fluid through the passageway 36 which will raise the ball 37 against the shoulder 40 and close off the flow of gas through the passageway. The plate 19 then acts as a piston and takes the place of the diaphragm 14 to exert force against the spring tending to close the valve.

For example, if the pressure of gas coming into a diaphragm actuated valve ranges from 500 to 1,000 pounds per square inch and the valve is set to maintain the pressure on the downstream side at 200 pounds per square inch, then if the pressure in the downstream side should go to 300 pounds per square inch, it is possible that the diaphragm might rupture in which event the spring would open the valve and pressure in the downstream side would reach dangerous values. However, in my valve operating mechanism, the piston takes over and regulates the pressure in the downstream side by closing the valve. The piston will not regulate the downstream pressure as closely as the diaphragm, but it will prevent high pressure from developing in the downstream side, for example, if the diaphragm is in operation, pressure on the downstream side will vary between 195 pounds per square inch when the valve is fully opened to 200 pounds per square inch when the valve is closed, whereas if the piston is used, the pressure will vary from 180 pounds per square inch to 200 pounds per square inch, but the valve will close at 200 pounds per square inch.

From the foregoing, it is apparent that I have invented valve actuating mechanism which can be used to operate valves subject to relatively high pressures and in which a diaphragm can be used to obtain close regulation of the downstream pressure. At the same time, the downstream side of the valve is protected against any failure of the diaphragm.

While I have described a presently preferred embodiment of my invention, it is to be understood that it may be otherwise embodied within the scope of the appended claims.

I claim:

1. A valve operating mechanism actuated by fluid pressure comprising,

A. a hollow cylinder open at one end and closed at the other end,

B. a flexible diaphragm extending across said open end and secured at its periphery to said cylinder,

C. a circular diaphragm plate,

(1) positioned in and movable in the cylinder (2) having a first portion smaller in area than the area of the open end of the cylinder, and said first portion being secured to the diaphragm,

(3) said plate also having a second portion of such diameter that it seals the cylinder adjacent said open end,

D. a passageway in said plate for fluid flow from the cylinder to space in the cylinder between the plate and the diaphragm,

E. a check valve in said passageway arranged to close upon a surge in fluid flow through the passageway,

F. an inlet for supplying fluid under pressure to said portion of the cylinder which is sealed by said plate,

G. a spring operatively connected to said diaphragm and positioned to exert a force on the diaphragm opposed to the force exerted by fluid pressure in the cylinder against the diaphragm, and

H. means for connecting said diaphragm to valve operating mechanism.

2. A valve operating mechanism actuated by fluid pressure comprising,

A. a hollow cylinder open at one end and closed at the other end,

B. a flexible diaphragm extending across said open end and secured at its periphery to said cylinder,

C. a circular diaphragm plate,

(1) positioned in and movable in the cylinder (2) having a first portion smaller in area than the area of the open end of the cylinder, said first portion being secured to the diaphragm,

(3) and having a seal mounted on its periphery for closing the space between the periphery of the plate and the inner surface of the cylinder,

D. a passageway in said plate for fluid flow from the cylinder to space in the cylinder between the plate and the diaphragm,

E. a check valve in said passageway arranged to close upon a surge in fluid flow through the passageway,

F. an inlet for supplying fluid under pressure to said portion of the cylinder which is sealed by said plate,

G. a spring operatively connected to said diaphragm and positioned to exert a force on the diaphragm opposed to the force exerted by fluid pressure in the cylinder against the diaphragm, and

H. means for connecting said diaphragm to valve operating mechanism.

3. A valve operating mechanism actuated by fluid pressure comprising,

A. a hollow cylinder open at one end and closed at the other end,

B. a flexible diaphragm extending across said open end and secured at its periphery to said cylinder,

C. a piston movable in said cylinder,

D. a passageway in said piston for fluid flow from the interior of the cylinder closed off by the piston to the portion of the cylinder between the diaphragm and the piston,

E. a check valve in said passageway arranged to close upon a surge in fluid flow through the passageway,

P. am inlet for supplying fluid under pressure to said portion of the cylinder which is sealed by the piston,

G. a spring operatively connected to said diaphragm and positioned to exert a force on the diaphragm opposed to the force exerted by fluid pressure in the cylinder against the diaphragm, and

H. means for connecting the diaphragm and the piston to valve operating mechanism.

4. A valve operating mechanism as described in claim 3 in which the check valve in the piston comprises a vertically extending portion of the passageway having a diameter larger than the diameter of the next succeeding portion of the passageway and a ball in said vertically extending portion having a diameter less than said passageway portion but larger than the diameter of the next succeeding portion, said ball and vertical portion of the passageway permitting flow of fluid under pressure through the passageway during normal operation but closing the passageway upon a surge in fluid pressure through said passageway.

References Cited in the file of this patent UNITED STATES PATENTS 2,618,908 Salter et al. Nov. 25, 1952 2,658,525 Shannon Nov. 10, 1953 2,707,966 Taplin May 10, 1955 2,923,314 Badger et al. Feb. 2, 1960 2,950,739 Lofink Aug. 30, 1960 

1. A VALVE OPERATING MECHANISM ACTUATED BY FLUID PRESSURE COMPRISING, A. A HOLLOW CYLINDER OPEN AT ONE END AND CLOSED AT THE OTHER END, B. A FLEXIBLE DIAPHRAGM EXTENDING ACROSS SAID OPEN END AND SECURED AT ITS PERIPHERY TO SAID CYLINDER, C. A CIRCULAR DIAPHRAGM PLATE, (1) POSITIONED IN AND MOVABLE IN THE CYLINDER (2) HAVING A FIRST PORTION SMALLER IN AREA THAN THE AREA OF THE OPEN END OF THE CYLINDER, AND SAID FIRST PORTION BEING SECURED TO THE DIAPHRAGM, (3) SAID PLATE ALSO HAVING A SECOND PORTION OF SUCH DIAMETER THAT IT SEALS THE CYLINDER ADJACENT SAID OPEN END, D. A PASSAGEWAY IN SAID PLATE FOR FLUID FLOW FROM THE CYLINDER TO SPACE IN THE CYLINDER BETWEEN THE PLATE AND THE DIAPHRAGM, E. A CHECK VALVE IN SAID PASSAGEWAY ARRANGED TO CLOSE UPON A SURGE IN FLUID FLOW THROUGH THE PASSAGEWAY, F. AN INLET FOR SUPPLYING FLUID UNDER PRESSURE TO SAID PORTION OF THE CYLINDER WHICH IS SEALED BY SAID PLATE, G. A SPRING OPERATIVELY CONNECTED TO SAID DIAPHRAGM AND POSITIONED TO EXERT A FORCE ON THE DIAPHRAGM OPPOSED TO THE FORCE EXERTED BY FLUID PRESSURE IN THE CYLINDER AGAINST THE DIAPHRAGM, AND H. MEANS FOR CONNECTING SAID DIAPHRAGM TO VALVE OPERATING MECHANISM. 